Aristotle: species will always be the same, 384-322 BCNicolas Steno: father of palentology, proposed rock formation and fossils are related, 1666Carolus Linnaeus: taxonomy, species unchanging (ideal structure and function), 1735Jean-Baptiste Lamarck: speices change over time (giraffs), inheritance of acquired characteristics, simple to complex forms, 1744-1829Count Buffon: speices change over time, different parts of world with similar climate have different species, climate change caused worldwide spread of species from orgin, proposed common ancestryGeorges Cuvier: founded paleontology (compared living animals with fossils), extinction, catastrophismCharles Lyell: uniformitarianism (geological features fromed by slow moving forces)Mathus: principle of population growth (exponential if resources were unlimited), struggle for existance

mechanisms for evolution propopsed by lamarck and dawin

lamarck: species passed on what they inherited during their lifetime (ex. if you had a child in summer while you were tan, the child would be tan)

darwin: all species related and decended from common ancestor, species evolve over time due to adaptation and natural selection,

lyell and malthus contributions to darwins hypothesis of evolution by natural selection

biogeography- saw similiar species in similar environments (species change over time to be suited to environment)

common animals in same area (all were descended from single species from a mainland)

modern synthesis

population processes (mutation, recombination, natural selection) account for orgin of species

molecular evolutionary biology (phylogenetic trees)

bacteria fight back

S. aureus began to acquire genes that confer resistance to other common antibiotics, carried on the same mobile

cassettes as mecA. The result was a bug that was both far more difficult to treat and, “pretty adaptive to surviving in hospitals.” multidrug-resistant MRSA.

structure of DNA and how mutation affects protein sequence, structure and function

DNA has a phosphate group, nitrogenous base (pyrimidine or purine)

mutation causes mismatches of pairs which causes a different rna code to be signaled. AA sequence affects how a protein folds and the folding determines function

changes in genotype may lead to changes in phenotype

Central Dogma

DNA-transcription-mRNA-translation-protein

DNA turned into mRNA which can relay the information and can call for the correct protein sequence

ultimate source of genetic variation

mutation

a mismatched base pair causes new protein which may or may not evolve a species

types of mutations

substitution (transition/transversion)

frameshift (deletion/insertion)

inversion

reciprocal translocation

mutation rate and natural selection

a high mutation rate could cause better fitness in a changing environment

mutation usually not good (deleterious)

why mutation is random

Mutations do not occur due to need.

ex. exposure to harmful chemicals may increase the mutation rate, but will not cause more mutations that make the organism resistant to those chemicals. In this respect, mutations are random—whether a particular mutation happens or not is generally unrelated to how useful that mutation would be.

gene pool

total of all the alleles of a gene that occur in a population

locus
allele
haplotype
gene flow

locus: location of gene or sequence on a chromosome

allele: alternative DNA sequences at the same physical locus, which may or may not result in different phenotypic traits

haplotype: combination of alleles at multiple loci that are transmitted together on the same chromosome

gene flow: the transfer of alleles of genes from one population to another.

Hardy Weinberg

conditions in which a population will not evolve

large popluations with random mating, allele frequencies will remain constant

parapatric: next to eachother (ex. divergence to feeding on different things)

allopatric: isolated distributions (migration)

scenario of genetic drift

a bunch of flowers on a hill, by change, pink are near the top, white flowers near the bottom.

flood comes through, washes away white flowers

new allele frequency with majority of flowers pink

scenario of natural selection

due to unknown bug, all fruits no longer grow in a niche. the birds in this niche now need to feed on insects that live inside the trees. the birds with narrow, longer beaks will survive better than those with fat, short beaks. therefore the narrow beaks will reporduce more.

experimental demonstration of natural selection

fish with 2 distinct colors

predators are introduced in the ecosystem that favor the bright colored fish

since the bright colored fish are being eaten, the drab fish have higher fitness and reproduce

conrol: normal ecosystem with out predators (has both colored fish0

adaptation
preadaptation
exaptation

adaptation: due to natrual selection, occurs due to selective pressure

preadatpation: already having a trait before using it (ex. dinosaurs having feathers for insulation before flying)

exaptation: change in function due to evolution?

natural selection does/doesnt

does: increases a trait, differences in reproductive success

doesnt: perfection (cant act on mutations that havent occured, tradeoff, developmental constraint), serve as a model of ethics or morality

argue "natural selection is random"

its not because:

those who survive are the ones who will mate

genetic variants that aid survival and reproduction are much more likely to become common than variants that don't

migration: movement of alleles between populationsgene flow: the transfer of alleles from the gene pool of one population to the gene pool of anothergenetric drift: chance or random influence on evolutioncoalescence: a sample of individuals from a population to trace all alleles of a gene shared by all members of the population to a single ancestral copy

rate of drift due to population size, migration, and selection

larger populations are less affected by drift

migration reduces effects of migration

selection increases genetic drifts effects

modes of natural selection

directional: homozygote advantage, over time favored allel frequency will equal 1 (fixed), reduces diversity, disadvantageous allel lost over time